my random monster chooser will only choose one monster. help?

so i made a script that chooses a random monster in the game and clones it and puts it in the workspace. but it only chooses shrek and says: "attempt to index local 'monster' (a number value)" help please ?

local h = Instance.new("Hint")
h.Parent = workspace
h.Text = ""


function choosemonster()
    local monsters = game.ReplicatedStorage.Monsters:GetChildren()
    local monster = math.random(1,#monsters)
    local wmonster = monsters[monster]:Clone()
    wmonster.Parent = workspace
    wmonster.Name = "Monster"
    h.Text = "Monster Chosen:"..monster.Name
end
function removemonster()
    if workspace.Monster ~= nil then
        workspace.Monster:Destroy()
    end
end
while wait() do
    h.Text = "Choosing Monster..."
    wait(5)
    choosemonster()
    wait(120)
    removemonster()
    h.Text = "The monster has disappeared..."
    wait(3)
end